Recirculating tube for water tube boilers



Aug. 1932- w. A. JONES 1,870,812

RECIRCULATING TUBE FOR WATER TUBE BOILERS Filed May 11, 1951 INVENTOR Patented Aug. 9, 1932 UNITED STATES- WILLIAM ANTHONY JONES, OF WEST N'EW BRIGHTON, NEW YORK,

IRECIRCULATING TUBE FOR WATER TUBE BOILERS Application filed May 11,

My invention provides inner recirculating tubes for returning surplus water from the upper ends to the lower ends of inclined steam generating tubes of water tube boilers, thus relieving the congestion in the connections to the steam drum and permitting operation at a higher rating ,for any given boiler.

The height of the steam drum of a water tube boiler, above the generating surface, is frequently determined by the height necessary to overcome resistance to circulation for the desired rating. For this height the difference in weight of water in the downtake tubes and headers and the weight of steam and water in the boiler tubes, the uptake headers and connecting tubes to drum, which difference in weight causes circulation, must be enough to overcome friction of flow and must give a velocity of flow .suflicient to carry to the drum the steam generated.

It has sometimes happened for a boiler that this height has not been enough to give the necessary velocity of circulation in cir culating tubes of the size used, with the result that steam has. accumulated in the upper tubes of an inclined water tube boiler and displaced the water in these tubes so that the tubes have become overheated and have been destroyed.

This action is indicated when upper tubes become over heated. For upper tubes, in general, overheating is not the result of scale deposited inside of the tubes and preventing them from contacting with contained water which is the usual cause of failure of the botupward through the hand hold header, marked, 16.

tom tubes when they burn.

Referring to the accompanying drawing;

Fig, 1 is a side view of the pressure parts of an inclined tube water tube boiler. v

F i 2 is an enlarged part section of the uptake header and generating tube with inner recirculating tu e.

Fig. 3 is an enlar ed part section of the downtake header and generating tube with inner recirculating tube.

Fig. 4 is an enlarged part section on line AA of generating tube with inner recirculating tube.

Fig. 5 is an entar ed part section on line BB of generating tu e with inner recirculat 1931. Serial No. 536,449.

ing tube showing slot in upper side of recir culating tube.- v

Fig. 6 is an enlarged part section showing engagement between upper end of generating tube and upper end of inner recirculating tube to keep the latter from sliding down ward except when it is desired to remove the inner tube. Slightly raising the upper end of the inner tube disengages it from the boiler tube so that the inner tube may be removed downward as'well as upward. 1

'Boile'r drum, 1, is connected by downtake tubes, 2, to downtake header, 3. Generating tubes, 4, connect downtake header, 3, to uptake header, 5,- which in turn is connected to drum by circulating tube, 6.

Downtake headers, 3, are connected by nipples, 7, to mud drum, 8.

Recirculating tube, 9, is supported concentric in generating tube, 4, by lugs, 20. Recirculating tube, 9, is shown with a slot, 10, in its upper side, extending from point, 11, to point, 12, having a length, 13.

Forward upper end of tube, 9, is bent downward at, 14, in the uptake header, 5, and is cut 75 oflf at, 15, and formed with a hook lug, 21, engaging the end of generating tube, 4. Hook lug, 21, extends only a distance, 22, below the inside of tube, 4, which distance is small enough so that by moving tube, 9, slightly forward and upward, it can be drawn downward through tube, 4, and through the handhole in the downtake header.

Tube, 9, may also be drawn forward and in the uptake Lbwer end of tube, 9, is also bent downward and cut off at, 18, so that it can be drawn-in either direction as described. 90

Curving downward the. upper end of inner tube, 9, causes upflowing water in the header,

5, to enter tube, 9, from below. Any steam which accompanies this water will pass up through the opening, 10, in the top of tube, 9, 5 to mingle with the steam and water flowing upward in outer tube, 4.

Slot, 10, is longer than what is required to pass steam upward and outward from tube, 9, to tube, 4, so that its lower end is available to Below opening, 10, the tube, 9, will be filled with water without steam, whose weight compared with the weight of the mixture of steam and water in tube, 4, insures a downflow in tube, 9.

Gurving downward the lower end of tube, 9, causes the'downflowing water in the downtake header, 3, to induce a 'downflow in tube,

9, also.

As pointed out above, limitation of capacity of connecting tube, 6, from uptake header to steam and water drum results in the steam in excess of that capacity, accumulating in the lpger part of the section above a line such as justas evidently steam would accumulate in-this space if circulation in tube, 6, were in'' teyrupted entirely.

Evidently if the capacity of flow in the up- 'take headers themselves is exceeded, steam will accumulate in tubes below the upper tubes. With very high ratings and headers of relatively small cross section for flow of steam and water, overheating of the third tube from the bottom has been observed. This condition will be improved by placing an inner tube in the third tube from the bottom so that excess water will not choke the header.

The total surface in contact with steam and water giving frictional resistance to flow is greater with the inner tube than without it and accordingly for the bottom tubes of the boiler which generally receive heat by radiation as well as by convection resulting in more steam than for an other tube of the boiler, no inner tube will e used.

Inner tubes will ordinarily be used for the upper row of tubes of boilers for high rating and for as many more rows of tubes below as are necessary for the particular service required.

High capacity of a boiler can ordinaril be obtained more cheaply by the use of t ese inner recirculating tubes than it can be by raising the drum, increasing the capacity of circulating tubes and the like, requiring more expense for boiler, more brick work,

higher building and the like.

The addition of the recirculating tubes in existing boilers will enable their circulation capacity to be increased with small expense.

The details of construction shown for illustration maybe varied without departing from my invention. 7

The fact that for clean tubes and very high ratings it is not thebottom tube but the upg per tubes that fail is explained by the above and the remed is the use of inner water reescribed.

I claim:

1. A water tube boiler having rows of straight inclined steam generating tubes with both ends connected to a steam drum, in combination with some inner concentric water recirculating'tubes with slots in the inner tubes.

2. A water tube boiler having straight inclined steam generating tubes in combination with some inner concentric water recirculating tubes connecting the same pressure parts that the generating tubes connect and With openings in the upper side of the inner tubes.

3. A water tube boiler having rows of straight inclined steam generating tubes with both ends connected to a steam drum, in combination with some inner concentric water recirculating tubes with openings in the upper side of the inner tubes and with the upper end ofthe inner tube bent downward for receiving upward flowing water.

4. A water tube boiler having rows of straight inclined steam generating tubes with both ends connected to a steam drum, in combination with some inner water recirculating tubes with openings in the upper side of the inner tubes and with the lower ends of the inner tubes bent downward for inducing downward flow of water within the inner tubes.

5. A water tube boiler having rows of straight inclined steam generating tubes with both ends connected to a steam drum, in combination with some inner concentric water recirculating tubes with openings in the upper side of the inner tubes and with the inner tube removably supported from the outer tube.

WILLIAM ANTHONY JONES. 

